Just over a week ago, I was asked by my wife and kids what I wanted for Father's Day. The next day I gave them a printout of the following plus a shot of the exact 49" x 97" x 3/4" MDF panel at Home Depot.

I said, I would like that sheet of wood cut to these specs.

I am a couple of hours into the project. Which isn't as far as you would think, but I am getting good and using a sircle jig with my router. I will post more pictures in the near future.

In the mean time, yes, that is almost 4 cuft...

I am using the full 4" port from Parts Express:

The woofer is aDayton Audio RSS315HF-4 12" Reference HF

And the Amp is a BASH 320 amp from SVS (same as what is in my current SVS 20-39PCi). I had an amp issue back in 2004 with my SVS and they sent me a brand new one. They never asked for the old one back, and in the middle of the "we shipped it" process, someone at AVS had a solution to my problem. I don't recall the solution, but it fixed what was happening and I never did swap amps around. SVS was told of what happened, and never asked for the new amp back even then.

OK. As promised, here are some subwoofer build pictures with a few comments:

Here are the basic cuts after getting the 3/4" MDF cut from Home Depot thanks to my wife and kids.

Here is my first shot at using a circle jig with my router. It was AWESOME and turned out very well.

This is the center brace that holds the middle of the sub together and hold the bottom of the port tube.

Next up is the bottom that holds the woofer itself. I used two pieces of 3/4" MDF. The center holes are the same, but the outside piece is also routed a little wider to allow the woofer to be recessed.

Then I worked on getting the top routed to hold the top of the port tube. It is nicely recessed too.

Next is the whole thing with all of the center brace holes routed again to make the holes round to allow for better air flow inside the box.

A closeup of the rounded center brace holes.

And a second closeup of the rounded corners.

Tomorrow I will cut out the hole for the amp and then start gluing things together. Then I caulk the seams. When that is cured, I will add the dampening foam to the inside. After that, I will put the last side panel on, and continue the assembly. The steps that are taking the longest amount of my time are pretty much done. Everything else will go pretty quickly but just need longer cure times in-between steps.

Hmm... It has been over a year since I did the modeling and I had someone else on the DIYAudio forums run it too. I guess my memory is wrong. The SVS goes down to 20 Hz with a slightly smaller enclosure, but I am guessing that the port must be a different length to get the tune. Maybe that is where I am off.

Nick, what do you consider might be "wrong" about your recollection? The 17.6Hz number is in the 17-18Hz range you mentioned. Of course, if you measured the volume of your enclosure and it's significantly less than the 5.83 cu. ft. "ideal" for a maximally flat response curve, then the extension at -3dB would be less and there would be more of a peak in the response.